The long-term objectives of this project are to increase the yield of developmentally-competent oocytes from rhesus monkey. The information acquired in the proposed studies should be useful with respect to in vitro maturation of human oocytes and oocytes from endangered animals, as well as to the basic scientific understanding of the process involved in normal oocyte development. The two specific aims of the project are (1) to determine optimal culture conditions (energy, substrates, nutrients and vitamins) for supporting acquisition of developmental competence during oocyte maturation in vitro, and (2) to determine if maintaining meiotic arrest for several days during culture of germinal vesicle stage oocytes enhances their subsequent developmental competence.